Electronic device with shielding structure and method of manufacturing the same
An electronic device includes a substrate, an active circuit, and a shielding structure. The active circuit is formed on the substrate. The shielding structure is disposed surrounding the active circuit, and includes a first heavy ion-doped region, first metal stack, second heavy ion-doped region, second metal stack and top metal. The first heavy ion-doped is formed in the substrate and located at a first side of the active circuit. The first metal stack is formed on the first heavy ion-doped region of the substrate, wherein the first metal stack is connected to a ground voltage. The second heavy ion-doped region is formed in the substrate and located at a second side of the active circuit. The second metal stack is formed on the second heavy ion-doped region of the substrate. The top metal is formed on the first metal stack and second metal stack and passing over the active circuit.
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1. Field of the Invention
The invention relates in general to an electronic device and method of manufacturing the same, and more particularly to an electronic device with shielding structure from crosstalk, noise and interferences, and method of manufacturing the same.
2. Description of the Related Art
When two circuits are side-by-side with each other, crosstalk and interference may occur if the operation frequencies of the circuits are high, especially at above RF frequency which is about a few tens of megahertz to several gigahertz or even higher. This kind of problem is especially severe if various kinds of circuits are integrated on the same substrate. For an example, in a typical system on chip (SOC) floor plan, radio frequency circuits such as a low noise amplifier (LNA) may sit next to high-speed logics or a power amplifier. Under such a situation, the performance and linearity of the LNA is usually degraded by crosstalk or interferences from the high-speed logic circuits or the power amplifier.
In case that the noisy sources 106 are high speed logics, the fast rise and fall time of their high-speed logic signals may contain many harmonics. If the high speed clock is a few tens or a few hundred megahertz, its fundamental frequency signal or harmonics may fall into the RF signal bands of the active circuit 104, and the small RF signal of the active circuit 104 will then be inevitably contaminated by these harmonics.
In case that the noisy sources 106 are power amplifiers, they usually generate RF signals with much larger power than that of the signal received by the active circuit 104. Once these large signals leak to the input of the active circuit 104, they may compress the active circuit 104, degrade its linearity, and cause more inter-modulations.
As a result, the crosstalk or interferences may degrade the signal integrity and circuit performance, and the performance degradation is especially severe in a SOC device in which various kinds of circuitries (RFIC, high-speed logic and analog circuits etc) are integrated on a single substrate.
SUMMARY OF THE INVENTIONThe invention is directed to an electronic device with shielding structure and method of manufacturing the same. Through the shielding structure formed on the substrate and located surrounding the active circuit, the active circuit can be effectively shielded from crosstalk, noise and interferences.
According to a first aspect of the present invention, an electronic device is provided. The electronic device comprises a substrate, an active circuit, and a shielding structure. The active circuit is formed on the substrate. The shielding structure is disposed surrounding the active circuit for shielding the active circuit from crosstalk, noise and interferences. The shielding structure comprises a first heavy ion-doped region, a first metal stack, a second heavy ion-doped region, a second metal stack and a top metal. The first heavy ion-doped is formed in the substrate and located at a first side of the active circuit. The first metal stack is formed on the first heavy ion-doped region of the substrate, wherein the first metal stack is connected to a ground voltage. The second heavy ion-doped region is formed in the substrate and located at a second side of the active circuit. The second metal stack is formed on the second heavy ion-doped region of the substrate. The top metal is formed on the first metal stack and the second metal stack and passing over the active circuit.
According to a second aspect of the present invention, a method of manufacturing an electronic device is provided. The method comprises providing a substrate comprising a region for forming the active circuit; forming a first heavy ion-doped region and a second heavy ion-doped region in the substrate and respectively at a first side and a second side of the region for forming the active circuit; forming a first metal stack and a second metal stack together with the active circuit respectively on the first heavy ion-doped region, the second heavy ion-doped region, and the region for forming the active circuit, wherein the first metal stack is connected to a ground voltage; and forming a top metal on the first metal stack and the second metal stack to pass over the active circuit.
The invention will become apparent from the following detailed description of the preferred but non-limiting embodiments. The following description is made with reference to the accompanying drawings.
The invention is directed to an electronic device having a shielding structure for the active circuit in order to resolve the problem of crosstalk, noise or interferences and maintain good signal integrity and circuit performance.
Referring to
In the embodiment, the electronic device 200 is exemplified to be implemented in a CMOS process, and the substrate 202 is a P-type substrate made of silicone. The active circuit 204 is formed on the substrate 202, which can be a noise source such as a clock generator, high-speed bus, high-speed digital circuit, driver or power amplifier, or a critical circuit to be shielded, such as a LNA. The shielding structure 210 is disposed surrounding the active circuit 204 for shielding the active circuit 204 from crosstalk with neighboring circuits, or from noise and interferences generated by noisy sources in the surroundings.
As shown in
The first heavy ion-doped region 211 is formed in the substrate 202 and located at a first side, such as the left side, of the active circuit 202. The first deep ion-doped region 218 is formed in the substrate 202 and located adjacent to the first heavy ion-doped region 211. The first deep ion-doped region 218 includes a third heavy ion-doped region 213 and has an ion-doping polarity opposite to that of the first heavy ion-doped region 211 and the same as that of the third heavy ion-doped region 213. The fourth heavy ion-doped region 214 is formed in the substrate 202 and located adjacent to adjacent to the first deep ion-doped region 218, and the fourth heavy ion-doped region 214 has an ion-doping polarity the same as that of the first heavy ion-doped region 211. In the embodiment, the first and fourth heavy ion-doped regions 211 and 214 are P+ diffusion regions. The first deep ion-doped region 218 is a deep N− well and the third heavy ion-doped region 213 is an N+ diffusion region.
The second heavy ion-doped region 212 is formed in the substrate 202 and located at a second side, such as the right side, of the active circuit 202. The second deep ion-doped region 212 is formed in the substrate 202 and located adjacent to the second heavy ion-doped region 212. The second deep ion-doped region 219 includes a fifth heavy ion-doped region 215 and has an ion-doping polarity opposite to that of the second heavy ion-doped region 212 and the same as that of the fifth heavy ion-doped region 215. The sixth heavy ion-doped region 216 is formed in the substrate 202 and located adjacent to the second deep ion-doped region 219, and the sixth heavy ion-doped region 216 has an ion-doping polarity the same as that of the second heavy ion-doped region 212. In the embodiment, the second and sixth heavy ion-doped regions 212 and 216 are P+ diffusion regions, the second deep ion-doped region 219 is a deep N− well, and the fifth heavy ion-doped region 215 is an N+ diffusion region.
Moreover, the first metal stack 220 is formed on the first heavy ion-doped region 211, the first deep ion-doped region 218 and the fourth heavy ion-doped region 214 of the substrate 202, and the first metal stack 220 is connected to a ground voltage. The second metal stack 230 is formed on the second heavy ion-doped region 212, the second deep ion-doped region 219 and the sixth heavy ion-doped region 216 of the substrate 202. The top metal 240 is formed on the first metal stack 220 and the second metal stack 230 and passes over the active circuit 204. The first metal stack 220, the second metal stack 230 and the top metal 240 are electrically isolated from the active circuit 204 by dielectric material 250, such as silicone dioxide (SiO2).
As shown in
Besides, as shown in
In the embodiment, N=9 and m=2, however, the invention is not limited thereto. For example, the active circuit 204 can be a conducting line consisted of a single metal layer, then the value N is 1, and the first side and the second side are two opposite sides of the conducting line. The value m can be any other even number, such as 0, i.e. the top metal 240 is directly formed upon the active circuit 204. Practically, a suitable distance between the top metal 240 and the active circuit 204, which is formed by interposing the dielectric layers 250, can help to reduce the parasitic capacitance of the active circuit 204.
Referring to
Although the shielding structure 210 is exemplified to shield the active circuit 204 from crosstalk or interference with the neighboring circuits 206 in the embodiment, the shielding structure 210 of the invention can be further used for shielding the active circuit 206 from any noise of devices, say, switches, or even from interference sources located outside the electronic device 200. As long as the shielding structure 210 can be provided in the electronic device 200 for shielding the active circuit 204 from crosstalk, noise or interference, all the alternatives are not depart from the scope of the invention.
It is noted that although the shielding structure 210 is exemplified to have two heavy ion-doped regions 211, 214 and a deep ion-doped region 218 at the left side of the active circuit 204 and two heavy ion-doped regions 212, 216 and a deep ion-doped region 219 at the right side of the active circuit 204 in the embodiment, the shielding structure 210 of the invention can also include only one heavy ion-doped region, such as the (P+) region 211 at one side, such as the left side, of the active circuit 204 and one heavy ion-doped region, such as (P+) region 212 at another side, such as the right side, of the active circuit 204. As long as the shielding structure 210 includes at least one heavy ion-doped region at one side of the active circuit 204 and at least one heavy ion-doped region at another side of the active circuit 204, the electric fields B1 and B2 generated from the active circuit 204 and passing through the substrate 202 can be blocked by the heavy ion-doped regions from reaching the neighboring circuits 206, all the alternatives are not apart from the scope of the invention.
Additionally, the shielding structure 210 of the invention is not limited to having only metal walls (metal stacks 220 and 230) disposed on the substrate 202 and located at two sides of the active circuit 204. Referring to
As a whole, as shown in
Although the shielding structure 210 is exemplified to have a 3-D rectangular structure including the first metal stack 220, the second metal stack 230, the third metal stack 260 and the fourth metal stack (totally four metal walls) incorporated with the heavy ion-doped regions 211, 212, 261 and 271 in the embodiment, the shielding structure 210 of the invention can also have a 3-D structure with any other shape, such as a circular shape, and can have only three metal walls, such as the metal stacks 220, 230 and 260 incorporated with the heavy ion-doped regions 211, 212 and 261, or only two metal walls, such as the metal stacks 220 and 230 incorporated with the heavy ion-doped regions 211 and 212. As long as the shielding structure can have at least two metal walls incorporated with two heavy ion-doped regions in the substrate at two sides of the active circuit, all the alternatives are not apart from the scope of the invention.
Referring to
It is noted that the active circuit 204 may include no contact diffusion region in the substrate 202, such as a conducting line. However, if the active circuit 204 includes contact diffusion regions, such as the regions 205, the contact diffusion regions 205 are formed together with the heavy ion-doped regions 211 and 212 in the step 620. Besides, the heavy ion-doped region 214 and deep ion-doped region 218 can be further formed in the substrate 202 and located at the left side of the active circuit 204 and the heavy ion-doped region 216 and deep ion-doped region 219 can be further formed in the substrate 202 and located at the right side of the active circuit 204 as shown in
Next, in step 630, form a first metal stack and a second metal stack together with the active circuit respectively on the first heavy ion-doped region, the second heavy ion-doped region, and the region for forming the active circuit, wherein the first metal stack is connected to a ground voltage.
For example, the active circuit 204 includes N semiconductor layers, which may include metal layers and dielectric layers, N is a natural number, and N is 9 in the active circuit 204 of
It is noted that in the embodiment where the first deep ion-doped region 218 and the fourth heavy ion-doped region 214 are formed adjacent to the first heavy ion-doped region 211 and the second deep ion-doped region 219 and the sixth heavy ion-doped region 216 are formed adjacent to the second heavy ion-doped region 212 (in the step 620), the first metal stack 220 is formed on the first heavy ion-doped region 211, the first deep ion-doped region 218 and the fourth heavy ion-doped region 214, and the second metal stack 230 is formed on the second heavy ion-doped region 212, the second deep ion-doped region 219 and the sixth heavy ion-doped region 216 in the step 630.
Finally, in step 640, form a top metal on the first metal stack and the second metal stack to pass over the active circuit. For example, form the top metal 240 on the first metal stack 220 and the second metal stack 230 to pass over the active circuit 204. In another embodiment, the third heavy ion-doped region 261 and the fourth heavy ion-doped region 271 can be further formed in the substrate 202 together with the heavy ion-doped regions 211 and 212 to form a rectangular shell as shown in
In the method of manufacturing the electronic device 200 of the embodiment, the shielding structure 210 is formed by using the available multiple metal layers in the process of fabricating the active circuit 204 (in step 630), and thus the signal integrity can be achieved meanwhile the on-chip crosstalk and interferences can be minimized.
Although the shielding structure 210 of the electronic device 200 is exemplified to be implemented in a CMOS process in the embodiment, the shielding structure 210 of the invention can also be implemented in a bipolar transistor process, a BiCMOS process or even a compound semiconductor process. As long as the shielding structure includes at least two heavy ion-doped regions in the substrate at two sides of the active circuit, at least two metal stacks formed on the two heavy ion-doped regions, and a top metal formed on the two metal stacks covering the active circuit to achieve the purpose of shielding the active circuit from crosstalk or interferences, all the alternatives are not apart from the scope of the invention.
The electronic device with shielding structure and method of manufacturing the same have the following advantages:
(1) By manufacturing a shielding structure for shielding the active circuit, any active circuit including a noisy source, such as a high-speed logic or power amplifier and a critical circuit to be protected can be effectively shielded from crosstalk, noise or interferences. Therefore, the issues of signal contamination by harmonics and linearity degradation of the active circuit in prior art can be effectively resolved.
(2) The shielding technique of the invention utilizing the available multiple metal layers in the fabrication process of the active circuit (e.g. an IC). Therefore, not only the on-chip crosstalk and interferences can be minimized but also the signal integrity can be achieved.
(3) By using the shielding technique of the invention, the on-chip RF isolation can be achieved without additional cost.
(4) The shielding structure of the invention is especially valuable in the implementation of SOC integration, and by using the shielding structure, the communication systems such as GSM, CDMA, portable digital TV, third-generation or fourth-generation mobile or personal communication systems can be integrated into a SOC with lower power consumption, lower cost and smaller size.
While the invention has been described by way of example and in terms of a preferred embodiment, it is to be understood that the invention is not limited thereto. On the contrary, it is intended to cover various modifications and similar arrangements and procedures, and the scope of the appended claims therefore should be accorded the broadest interpretation so as to encompass all such modifications and similar arrangements and procedures.
Claims
1. An electronic device, comprising:
- a substrate;
- an active circuit, formed on the substrate; and
- a shielding structure, disposed surrounding the active circuit for shielding the active circuit from crosstalk, noise and interferences, the shielding structure comprising: a first heavy ion-doped region, formed in the substrate and located at a first side of the active circuit; a first metal stack, formed on the first heavy ion-doped region of the substrate, wherein the first metal stack is connected to a ground voltage; a second heavy ion-doped region, formed in the substrate and located at a second side of the active circuit; a second metal stack, formed on the second heavy ion-doped region of the substrate; and a top metal, formed on the first metal stack and the second metal stack and passing over the active circuit.
2. The electronic device according to claim 1, comprising a radio frequency integrated circuit (RFIC), a mixed-signal integrated circuit, a high-speed digital circuit or a system-on-chip (SOC) integrated circuit.
3. The electronic device according to claim 1, wherein the active circuit is selected from a group of a clock generator, a high-speed bus, a high-speed digital circuit, a driver, a power amplifier, and a low noise amplifier (LNA).
4. The electronic device according to claim 1, being implemented in a complementary metal oxide semiconductor (CMOS), bipolar transistor, BiCMOS or compound semiconductor process.
5. The electronic device according to claim 1, wherein the first metal stack, the second metal stack and the top metal are electrically isolated from the active circuit by dielectric material.
6. The electronic device according to claim 1, further comprising:
- a first deep ion-doped region, formed in the substrate and located under the first metal stack and adjacent to the first heavy ion-doped region, wherein the first deep ion-doped region comprises a third heavy ion-doped region and has an ion-doping polarity opposite to that of the first heavy ion-doped region and the same as that of the third heavy ion-doped region;
- a fourth heavy ion-doped region, formed in the substrate and located adjacent to the first deep ion-doped region, wherein the fourth heavy ion-doped region has an ion-doping polarity the same as that of the first heavy ion-doped region;
- a second deep ion-doped region, formed in the substrate and located under the second metal stack and adjacent to the second heavy ion-doped region, wherein the second deep ion-doped region comprises a fifth heavy ion-doped region and has an ion-doping polarity opposite to that of the second heavy ion-doped region and the same as that of the fifth heavy ion-doped region; and
- a sixth heavy ion-doped region, formed in the substrate and located adjacent to the second deep ion-doped region, wherein the sixth heavy ion-doped region has an ion-doping polarity the same as that of the second heavy ion-doped region.
7. The electronic device according to claim 6, being implemented in a CMOS process, wherein the substrate is a P-type substrate, the first heavy ion-doped region, the second heavy ion-doped region, the fourth heavy ion-doped region, and the sixth heavy ion-doped region are P+ diffusion regions, the first deep ion-doped region and the second deep ion-doped region are deep N− wells, and the third heavy ion-doped region and the fifth heavy ion-doped region are N+ diffusion regions.
8. The electronic device according to claim 1, wherein the active circuit has N semiconductor layers, the first metal stack and the second metal stack respectively comprise N layers of first metal and second metal formed corresponding to the N semiconductor layers, and m layers of first metal and second metal formed on the N layers of first metal and second metal corresponding to m dielectric layers formed on the active circuit, N is a natural number and m is an even number.
9. The electronic device according to claim 8, wherein the first metal and the second metal formed corresponding to a dielectric layer of the active circuit are via or contact metals, and the first metal and the second metal formed corresponding to a metal layer of the active circuit are metal layers.
10. The electronic device according to claim 8, wherein the thickness of the top metal is about twice the thickness of the first metal and the second metal.
11. The electronic device according to claim 1, wherein the active circuit is a conducting line consisted of a single metal layer, and the first side and the second side are two opposite sides of the conducting line.
12. The electronic device according to claim 1, wherein the shielding structure further comprises:
- a third heavy ion-doped region, formed in the substrate and located at a third side of the active circuit; and
- a third metal stack, formed on the third heavy ion-doped region of the substrate and connected underneath to the top metal.
13. The electronic device according to claim 12, wherein the shielding structure further comprises:
- a fourth heavy ion-doped region, formed in the substrate and at a fourth side of the active circuit; and
- a fourth metal stack, formed on the fourth heavy ion-doped region of the substrate and connected underneath to the top metal.
14. The electronic device according to claim 13, wherein the first metal stack, the second metal stack, the third metal stack, the four metal stack and the top metal form a rectangular housing covering the active circuit, and the first heavy ion-doped region, the second heavy ion-doped region, the third heavy ion-doped region and the fourth ion-doped region are connected together to form a rectangular shell.
15. A method of manufacturing an electronic device, the electronic device comprising an active circuit, the method comprising:
- providing a substrate comprising a region for forming the active circuit;
- forming a first heavy ion-doped region and a second heavy ion-doped region in the substrate and respectively at a first side and a second side of the region for forming the active circuit;
- forming a first metal stack and a second metal stack together with the active circuit respectively on the first heavy ion-doped region, the second heavy ion-doped region, and the region for forming the active circuit, wherein the first metal stack is connected to a ground voltage; and
- forming a top metal on the first metal stack and the second metal stack to pass over the active circuit.
16. The method according to claim 15, wherein the active circuit comprises N semiconductor layers, N is a natural number, and the step of forming a first metal stack and a second metal stack together with the active circuit further comprises sequentially forming N layers of first metal on the first heavy ion-doped region, N layers of second metal on the second heavy ion-doped region, and the N semiconductor layers of the active circuit on the substrate, the first metal and the second metal formed corresponding to a metal layer of the active circuit are metal layers, and the first metal and the second metal formed corresponding to a dielectric layer of the active circuit are via or contact metals.
17. The method according to claim 16, wherein the step of forming a first metal stack and a second metal stack together with the active circuit further comprises sequentially forming m dielectric layers on the N semiconductor layers of the active circuit, and forming m layers of first metal and second metal respectively on the N layers of first metal and second metal, m is an even number.
18. The method according to claim 16, wherein the thickness of the top metal is about twice the thickness of the first metal and the second metal
19. The method according to claim 15, wherein the active circuit is a conducting line with a single metal layer, and the first side and the second side are two opposite sides of the active circuit.
20. The method according to claim 15, wherein the electronic device is implemented in a complementary metal oxide semiconductor (CMOS), bipolar transistor, BiCMOS or compound semiconductor process.
21. The method according to claim 15, wherein the step of forming a first heavy ion-doped region and a second heavy ion-doped region in the substrate further comprises:
- forming a first deep ion-doped region in the substrate and adjacent to the first heavy ion-doped region, and forming a third heavy ion-doped region in the first deep ion-doped region, wherein the first deep ion-doped region has an ion-doping polarity opposite to that of the first heavy ion-doped region and the same as that of the third heavy ion-doped region;
- forming a fourth heavy ion-doped region in the substrate and adjacent to the first deep ion-doped region, wherein the fourth heavy ion-doped region has an ion-doping polarity the same as that of the first heavy ion-doped region;
- forming a second deep ion-doped region in the substrate and adjacent to the second heavy ion-doped region, and forming a fifth heavy ion-doped region in the second deep ion-doped region, wherein the second deep ion-doped region has an ion-doping polarity opposite to that of the second heavy ion-doped region and the same as that of the fifth heavy ion-doped region; and
- forming a sixth heavy ion-doped region in the substrate and adjacent to the second deep ion-doped region, wherein the sixth heavy ion-doped region has an ion-doping polarity the same as that of the second heavy ion-doped region;
- wherein the step of forming a first metal stack and a second metal stack further comprises:
- forming the first metal stack on the first heavy ion-doped region, the first deep ion-doped region and the fourth heavy ion-doped region; and
- forming the second metal stack on the second heavy ion-doped region, the second deep ion-doped region and the sixth heavy ion-doped region.
22. The method according to claim 21, wherein the electronic device is implemented in a CMOS process, the substrate is a P-type substrate, the first heavy ion-doped region, the second heavy ion-doped region, the fourth heavy ion-doped region, and the sixth heavy ion-doped region are P+ diffusion regions, the first deep ion-doped region and the second deep ion-doped region are deep N− wells, and the third heavy ion-doped region and the fifth heavy ion-doped region are N+ diffusion region.
23. The method according to claim 15, wherein the step of forming a first heavy ion-doped region and a second heavy ion-doped region in the substrate further comprises:
- forming a third heavy ion-doped region in the substrate and at a third side of the active circuit;
- wherein the step of forming a first metal stack and a second metal stack together with the active circuit further comprises:
- forming a third metal stack on the third heavy ion-doped region of the substrate;
- wherein the step of forming the top metal comprises forming the top metal on the third metal stack.
24. The method according to claim 23, wherein the step of forming a first heavy ion-doped region and a second heavy ion-doped region in the substrate further comprises:
- forming a fourth heavy ion-doped region in the substrate and at a fourth side of the active circuit;
- wherein the step of forming a first metal stack and a second metal stack together with the active circuit further comprises:
- forming a fourth metal stack on the fourth heavy ion-doped region of the substrate;
- wherein the step of forming the top metal comprises forming the top metal on the fourth metal stack.
25. The method according to claim 24, wherein the first metal stack, the second metal stack, the third metal stack, the four metal stack and the top metal form a rectangular housing covering the active circuit, and the first heavy ion-doped region, the second heavy ion-doped region, the third heavy ion-doped region and the fourth ion-doped region are connected together to form a rectangular shell.
Type: Application
Filed: Mar 26, 2008
Publication Date: Oct 1, 2009
Patent Grant number: 7804158
Applicant: MaxRise Inc. (Hsin-Chu)
Inventor: Hwey-Ching Chien (San Diego, CA)
Application Number: 12/076,982
International Classification: H01L 23/552 (20060101); H01L 21/50 (20060101);